Bruce Schneier's FAQ concerning Microsoft's PPTP Implementation
Bruce Schneier Analysis of the Microsoft PPTP implementation. Why is PPTP bad.
Freeswan and a Cisco PIX 501
Creating an interoperable VPN using the free FreeSWAN/Openswan and a Cisco PIX 501.
IPSec/L2TP Tunnelling with Linux-2.6 and Racoon
This tutorial describes an IPsec/L2TP setup using Racoon and l2tpd.
Linux VPN Howto using SSH and PPP
This howto describes the setup of a simple VPN using ssh and ppp.
OpenVPN 2.0 HOWTO
This howto describes the setup of the IPsec alternative OpenVPN, which is available for Win32, MacOS X and Unix-based Operating Systems.
OpenVPN using X.509 certificates
This document explains how to deploy a VPN using OpenVPN and OpenSSL.
Replacing a Windows PPTP server with Linux
Replacing a Windows PPTP server with Linux PopTop.
Using a Linux L2TP/IPsec VPN server
This document gives you the background and show the steps for implementing an L2TP/IPsec based VPN using Linux, Windows and MacOSX